Copper-base alloys are well-known materials of construction for discrete alloy parts, for example bushings, bearings, and structural parts. It is known to manufacture such copper-base alloy parts by powder metallurgical methods involving the sintering of green bodies having substantially the desired shape of, and proportionally sized to, the final article. Thus, for example, U.S. Pat. No. 2,301,721 discloses the manufacture of a composite floor product article by sintering equal volumes of an abrasive material and a metal bond together, preferably at about 800.degree. C. for 5 hours, with the metal bond being a mixture of copper, nickel and tin elemental powders, and U.S. Pat. No. 3,453,103 discloses the manufacture of alloy articles by sintering at 760.degree. C. to 830.degree. C. for 15 to 60 minutes green compacts made by compaction of a mixture of copper (balance), nickel (4.5 to 5.5 wt. %), tin (7 to 8 wt. %) and graphite (0.25 to 4 wt. %) elemental powders.
U.S. Pat. No. 4,373,970 discloses powder metallurgical processes for preparing stock material of indefinite length (strip, sheet, rod, wire, etc.) of a copper-nickel-tin spinodal alloy containing from about 5 to 35 wt. % nickel, from about 7 to 13 wt. % tin and the balance copper. The preferred powder metallurgical process disclosed in this patent includes the steps of compacting a prealloyed or elemental powder to a green form, sintering the green form at a temperature of from about 1200.degree. F. to 1900.degree. F. for at least about one minute, cooling the sintered strip at a rate sufficient to prevent age hardening and embrittlement, cold working the cooled sintered material to a substantially fully dense final gage, and annealing the cold worked material and quenching it at a rate sufficient to retain substantially all alpha phase. Although this process has been used with considerable success in the commercial manufacture of Pfinodal.RTM. copper-nickel (15 wt. %)-tin (8 wt. %) strip (Pfizer Inc.; New York, N.Y.), a product with an excellent combination of strength, formability, ductility and electrical conductivity characteristics, its adaptability to the manufacture of discrete alloy parts (e.g. bearings and bushings) has heretofore been uncertain, principally because of the fact that full densification is typically not achieved in powder metallurgical discrete parts manufacture.